[2] He served under David Lloyd George as Postmaster General from 1916 to 1921 and was sworn of the Privy Council in 1916.

[3] In 1921 he was raised to the peerage as Baron Illingworth, of Denton in the West Riding of the County of York.

[5] Lord Illingworth married firstly Annie Elizabeth, daughter of Isaac Holden Crothers, in 1895.

From 1928 to his death, Illingworth leased a town house at 39/44 Grosvenor Square in Mayfair.

His second wife died in 1986, having become before her death the victim of a massive defrauding of her estate by her niece who had been investigated over the murder of Simon Dale, the latter's ex-husband.